The present invention relates to a control device for an electrically driven door and, in particular, to a control device that drives an electrically driven door safely when foreign matter is pinched by the door.
In an electrically driven door driven by an electric motor, for example, a side sliding door of a rail car, the detection that a passenger or foreign matter, such as passenger's belonging, is pinched by the door when the door is closed (a so-called “door pinch” state) is a very important function in securing the safety of the passenger. For this reason, a door pinch detecting device has been proposed to detect the door pinch state.
JP-A 3-189265, for example, discloses a device that includes: a speed detecting unit for detecting the opening/closing speed of a door; a position detecting unit for detecting that the door is located at a middle position in the opening/closing operation; a determination unit that receives the detection results of the speed detecting unit and the position detecting unit and that determines whether the opening/closing speed of the door located at the middle position of the opening/closing operation is zero, in a decreasing state, or in a minus state; and a notification unit that outputs a signal for notifying that foreign matter is pinched by the tip of the door when the determination unit determines that the opening/closing speed of the door located at the middle position of the opening/closing operation is zero, in the decreasing state, or in the minus state ( ). Moreover, in the same patent document, a door pinch detecting device is described that has a pressure sensing sensor disposed in a rubber piece fitted to the tip of the rail car door, and which detects foreign matter being pinched by the door by a change in pressure.
When the occurrence of door pinch is detected by the door pinch detecting device of the type described above, either decreases the thrust of the door, opens the door a specified distance in a direction to fully open the door or the door is opened to a fully opened position. Using one of these options, it is then possible to relieve a passenger pinched by the door or to pull off the passenger's belongings being pinched by the door.
However, in the above-described device, when it is determined that the door is not brought to a totally closed position or that the opening/closing speed of the door at a middle position in the opening/closing operation is zero, in the decreasing state, or in the minus state, a signal for notifying that foreign matter is pinched by the tip of the door is output. Thus, as a result, the above-described device is constructed so as to detect the door pinch state by detecting that the door has been brought into the door pinch state, in other words, by detecting that the door pinch state has already occurred. As a result, the foreign matter pinched by the door continuously undergoes pressure and, in particular, when a passenger getting on or off is pinched by the door, the passenger continuously undergoes pressure until the door pinch state is detected thereby causing the passenger to feel some pain due to the applied pressure.
Moreover, to increase the sensitivity with which the door pinch state is detected, the rigidity of the door, in particular, the rigidity of rubber disposed at the tip of the door (hereinafter referred to as “door tip rubber”), needs to be increased. Although the increase in the rigidity of the rubber makes detection of the door pinch state easier, it also results in increasing the pressing pain when the door pinch state occurs, which presents a not-yet-solved problem that increasing the pressing pain experienced by the passenger is not preferable from the viewpoint of safety.
Thus, it would be desirable to provide a control device of an electrically driven door that can increase the sensitivity with which the door pinch state is detected, and which can prevent a passenger from being pressed when the door pinch state occurs and the passenger is pinched by the tip of the door.
Moreover, in an electrically driven door for a rail car, when a phenomenon occurs that foreign matter is pulled into a gap between the electrically driven door and a car body during a door opening/closing operation (also referred to as “opening door pinch”), it is difficult to determine whether or not the electrically driven door reaches a fully open position, because a maximum opening size of the electrically driven door cannot be accurately determined due to variations in the manufacturing accuracy of the car body. Thus, there is presented a not-yet-solved problem that the relate art cannot provide a more effective determination means than one that uses a decrease in door speed to determine the above-mentioned phenomenon.
Further, the door for a rail car is provided with a seal rubber for preventing a draft entering from the gap of the door while the rail car is running, and a damper for pressing the door in a direction vertical to a direction in which the door is operated so as to prevent the door from being rattled by the vibration caused when the rail car is running. Thus, even when the door is normally operated, a mechanical resistant force to an electric motor for driving the door varies from moment to moment according to the position of the door in the operation of opening/closing the door. Hence, when a door thrust is limited, it is difficult to manage a final door thrust only by limiting the thrust or torque of the electric motor, which is a not-yet-solved problem. In other words, there is presented such a not-yet-solved problem that since an increase or decrease in the mechanical resistant force varies a net door thrust, it is likely that when the margin of the door thrust becomes insufficient, normal operation will be prevented or that, when the door thrust becomes excessive at the time of door pinch, safety will be compromised.
Accordingly, it would also be desirable to provide a control device of an electrically driven door that can quickly detect the door pinch state and that can manage the net thrust of the door also to a mechanical resistant force when the door is operated.